Convective boundary layer slab model / Samuli Launiainen 20.09.2018
Simple Python-implementation of convective mixed boundary layer model. Based maily on:
- Janssen & Pozzer, 2015. Geosci Model Devel. 8, 453 - 471.: https://www.geosci-model-dev.net/8/453/2015/gmd-8-453-2015.pdf
- Stull, 1988. Boundary layer -handbook
- Matlab-code of Gaby Katul (lifting condensation level)
Parts:
- mxl - model code
- mxl_demo - simple demonstration of MXL-model using one daytime data from Hyytiälä.
TODO:
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Nocturnal boundary layer height development OR (at minimum) initial height and scalar condentrations in the morning. Zilitinkevich, 1972. 'Equilibrium height'
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MXL and LCL predictions: validate against Hyde soundings and ceilometer data?
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For coupling with APES canopy MLM we need to:
- define constant height z at which the 'hand-shaking' of MLM and MXL occurs (50m ?)
- MLM needs U & ustar at z as forcing; how to formulate these with MXL -approach? Do we need to include stability effect on scalar transport within canopy?
- Do we impose PAR, NIR and LW at z from external forcing, OR should we at some stage think cloud development and model radiation budget. Same concerns U & ustar. For MXL wind budget, we need momentum flux at the surface, or use imposed ustar
- For coupled simulations, where heat, water vapor and co2 fluxes are computed using canopy MLM, we need reasonable development of nocturnal boundary layer. In principle, we want forcings (in particular T and LWin) to be realistic for nocturnal canopy MLM simulations. And, we need a reference volume (bl height) into / from which the canopy sources / sinks affect. The nocturnal mass / energy exchange then leads to initial conditions (theta, q, co2) at next morning.